1. General concept

1.1 Principle

The design of a fire-resistant structure relies on a thorough understanding of the interactions between material and heat. In addition to reduced strength and stiffness, exposure to high temperatures can also lead to thermal expansion of the material, which can compromise structural integrity. It should be noted that some materials, such as concrete and wood, can suffer irreversible damage when exposed to fire. The aim of this section is to detail how the strength and stiffness of steel change with temperature, and to discuss the impact of these variations on the stability of structures in the event of fire.